The Experts below are selected from a list of 48 Experts worldwide ranked by ideXlab platform

Shinji Kageyama - One of the best experts on this subject based on the ideXlab platform.

  • determination of growth hormone secretagogue Pralmorelin ghrp 2 and its metabolite in human urine by liquid chromatography electrospray ionization tandem mass spectrometry
    Rapid Communications in Mass Spectrometry, 2010
    Co-Authors: Masato Okano, Mitsuhiko Sato, Ayako Ikekita, Shinji Kageyama
    Abstract:

    GHRP-2 (Pralmorelin, D-Ala-D-(β-naphthyl)-Ala-Ala-Trp-D-Phe-Lys-NH2), which belongs to a class of growth hormone secretagogue (GHS), is intravenously used to diagnose growth hormone (GH) deficiency. Because it may be misused in expectation of a growth-promoting effect by athletes, the illicit use of GHS by athletes has been prohibited by the World Anti-Doping Agency (WADA). Therefore, the mass spectrometric identification of urinary GHRP-2 and its metabolite D-Ala-D-(β-naphthyl)-Ala-Ala-OH (AA-3) was studied using liquid chromatography/electrospray ionization tandem mass spectrometry for doping control purposes. The method consists of solid-phase extraction using stable-isotope-labeled GHRP-2 as an internal standard and subsequent ultra-performance liquid chromatography/tandem mass spectrometry, and the two target peptides were determined at urinary concentrations of 0.5–10 ng/mL. The recoveries ranged from 84 to 101%, and the assay precisions were calculated as 1.6–3.8% (intra-day) and 1.9–4.3% (inter-day). Intravenous administration of GHRP-2 in ten male volunteers was studied to demonstrate the applicability of the method. In all ten cases, unchanged GHRP-2 and its specific metabolite AA-3 were detected in urine. Copyright © 2010 John Wiley & Sons, Ltd.

  • Determination of growth hormone secretagogue Pralmorelin (GHRP-2) and its metabolite in human urine by liquid chromatography/electrospray ionization tandem mass spectrometry.
    Rapid Communications in Mass Spectrometry, 2010
    Co-Authors: Masato Okano, Mitsuhiko Sato, Ayako Ikekita, Shinji Kageyama
    Abstract:

    GHRP-2 (Pralmorelin, D-Ala-D-(β-naphthyl)-Ala-Ala-Trp-D-Phe-Lys-NH2), which belongs to a class of growth hormone secretagogue (GHS), is intravenously used to diagnose growth hormone (GH) deficiency. Because it may be misused in expectation of a growth-promoting effect by athletes, the illicit use of GHS by athletes has been prohibited by the World Anti-Doping Agency (WADA). Therefore, the mass spectrometric identification of urinary GHRP-2 and its metabolite D-Ala-D-(β-naphthyl)-Ala-Ala-OH (AA-3) was studied using liquid chromatography/electrospray ionization tandem mass spectrometry for doping control purposes. The method consists of solid-phase extraction using stable-isotope-labeled GHRP-2 as an internal standard and subsequent ultra-performance liquid chromatography/tandem mass spectrometry, and the two target peptides were determined at urinary concentrations of 0.5–10 ng/mL. The recoveries ranged from 84 to 101%, and the assay precisions were calculated as 1.6–3.8% (intra-day) and 1.9–4.3% (inter-day). Intravenous administration of GHRP-2 in ten male volunteers was studied to demonstrate the applicability of the method. In all ten cases, unchanged GHRP-2 and its specific metabolite AA-3 were detected in urine. Copyright © 2010 John Wiley & Sons, Ltd.

Masato Okano - One of the best experts on this subject based on the ideXlab platform.

  • determination of growth hormone secretagogue Pralmorelin ghrp 2 and its metabolite in human urine by liquid chromatography electrospray ionization tandem mass spectrometry
    Rapid Communications in Mass Spectrometry, 2010
    Co-Authors: Masato Okano, Mitsuhiko Sato, Ayako Ikekita, Shinji Kageyama
    Abstract:

    GHRP-2 (Pralmorelin, D-Ala-D-(β-naphthyl)-Ala-Ala-Trp-D-Phe-Lys-NH2), which belongs to a class of growth hormone secretagogue (GHS), is intravenously used to diagnose growth hormone (GH) deficiency. Because it may be misused in expectation of a growth-promoting effect by athletes, the illicit use of GHS by athletes has been prohibited by the World Anti-Doping Agency (WADA). Therefore, the mass spectrometric identification of urinary GHRP-2 and its metabolite D-Ala-D-(β-naphthyl)-Ala-Ala-OH (AA-3) was studied using liquid chromatography/electrospray ionization tandem mass spectrometry for doping control purposes. The method consists of solid-phase extraction using stable-isotope-labeled GHRP-2 as an internal standard and subsequent ultra-performance liquid chromatography/tandem mass spectrometry, and the two target peptides were determined at urinary concentrations of 0.5–10 ng/mL. The recoveries ranged from 84 to 101%, and the assay precisions were calculated as 1.6–3.8% (intra-day) and 1.9–4.3% (inter-day). Intravenous administration of GHRP-2 in ten male volunteers was studied to demonstrate the applicability of the method. In all ten cases, unchanged GHRP-2 and its specific metabolite AA-3 were detected in urine. Copyright © 2010 John Wiley & Sons, Ltd.

  • Determination of growth hormone secretagogue Pralmorelin (GHRP-2) and its metabolite in human urine by liquid chromatography/electrospray ionization tandem mass spectrometry.
    Rapid Communications in Mass Spectrometry, 2010
    Co-Authors: Masato Okano, Mitsuhiko Sato, Ayako Ikekita, Shinji Kageyama
    Abstract:

    GHRP-2 (Pralmorelin, D-Ala-D-(β-naphthyl)-Ala-Ala-Trp-D-Phe-Lys-NH2), which belongs to a class of growth hormone secretagogue (GHS), is intravenously used to diagnose growth hormone (GH) deficiency. Because it may be misused in expectation of a growth-promoting effect by athletes, the illicit use of GHS by athletes has been prohibited by the World Anti-Doping Agency (WADA). Therefore, the mass spectrometric identification of urinary GHRP-2 and its metabolite D-Ala-D-(β-naphthyl)-Ala-Ala-OH (AA-3) was studied using liquid chromatography/electrospray ionization tandem mass spectrometry for doping control purposes. The method consists of solid-phase extraction using stable-isotope-labeled GHRP-2 as an internal standard and subsequent ultra-performance liquid chromatography/tandem mass spectrometry, and the two target peptides were determined at urinary concentrations of 0.5–10 ng/mL. The recoveries ranged from 84 to 101%, and the assay precisions were calculated as 1.6–3.8% (intra-day) and 1.9–4.3% (inter-day). Intravenous administration of GHRP-2 in ten male volunteers was studied to demonstrate the applicability of the method. In all ten cases, unchanged GHRP-2 and its specific metabolite AA-3 were detected in urine. Copyright © 2010 John Wiley & Sons, Ltd.

Yasufumi Sawada - One of the best experts on this subject based on the ideXlab platform.

  • physiologically based pharmacokinetic model for Pralmorelin hydrochloride in rats
    Drug Metabolism and Disposition, 2005
    Co-Authors: Risa Nasu, Yoichi Kumagai, Hirokuni Kogetsu, Masayuki Tsujimoto, Hisakazu Ohtani, Yasufumi Sawada
    Abstract:

    Pralmorelin hydrochloride (Pralmorelin), consisting of six amino acid residues, is a growth hormone-releasing peptide. The aim of this study is to analyze the pharmacokinetics of Pralmorelin after intravenous bolus administration to rats, and to develop a physiologically based pharmacokinetic (PB-PK) model to describe and predict the concentrations of Pralmorelin in blood and tissues. Pralmorelin (3 mg/kg) was administered intravenously to 24 Sprague-Dawley rats. Groups of three rats were sacrificed by decapitation at each designated time point (up to 4 h), and plasma and tissues (brain, lung, heart, liver, kidney, small intestine, muscle, adipose, and skin) were collected. Bile was also pooled until decapitation. The concentration of Pralmorelin in samples was determined by liquid chromatography-tandem mass spectrometry. Plasma concentrations of Pralmorelin declined rapidly in a biexponential manner. Biliary excretion of Pralmorelin was so rapid that 80% of the dose was recovered unchanged in the bile within 1 h after administration. The distribution parameters in each tissue were obtained by using a hybrid model and an integration plot. They revealed that the distribution of Pralmorelin into liver was blood flow-limited, and its distribution was permeability-limited in all other tissues. The PB-PK model developed in this study well described the time courses of Pralmorelin concentration in the blood and tissues of rats.

Mitsuhiko Sato - One of the best experts on this subject based on the ideXlab platform.

  • determination of growth hormone secretagogue Pralmorelin ghrp 2 and its metabolite in human urine by liquid chromatography electrospray ionization tandem mass spectrometry
    Rapid Communications in Mass Spectrometry, 2010
    Co-Authors: Masato Okano, Mitsuhiko Sato, Ayako Ikekita, Shinji Kageyama
    Abstract:

    GHRP-2 (Pralmorelin, D-Ala-D-(β-naphthyl)-Ala-Ala-Trp-D-Phe-Lys-NH2), which belongs to a class of growth hormone secretagogue (GHS), is intravenously used to diagnose growth hormone (GH) deficiency. Because it may be misused in expectation of a growth-promoting effect by athletes, the illicit use of GHS by athletes has been prohibited by the World Anti-Doping Agency (WADA). Therefore, the mass spectrometric identification of urinary GHRP-2 and its metabolite D-Ala-D-(β-naphthyl)-Ala-Ala-OH (AA-3) was studied using liquid chromatography/electrospray ionization tandem mass spectrometry for doping control purposes. The method consists of solid-phase extraction using stable-isotope-labeled GHRP-2 as an internal standard and subsequent ultra-performance liquid chromatography/tandem mass spectrometry, and the two target peptides were determined at urinary concentrations of 0.5–10 ng/mL. The recoveries ranged from 84 to 101%, and the assay precisions were calculated as 1.6–3.8% (intra-day) and 1.9–4.3% (inter-day). Intravenous administration of GHRP-2 in ten male volunteers was studied to demonstrate the applicability of the method. In all ten cases, unchanged GHRP-2 and its specific metabolite AA-3 were detected in urine. Copyright © 2010 John Wiley & Sons, Ltd.

  • Determination of growth hormone secretagogue Pralmorelin (GHRP-2) and its metabolite in human urine by liquid chromatography/electrospray ionization tandem mass spectrometry.
    Rapid Communications in Mass Spectrometry, 2010
    Co-Authors: Masato Okano, Mitsuhiko Sato, Ayako Ikekita, Shinji Kageyama
    Abstract:

    GHRP-2 (Pralmorelin, D-Ala-D-(β-naphthyl)-Ala-Ala-Trp-D-Phe-Lys-NH2), which belongs to a class of growth hormone secretagogue (GHS), is intravenously used to diagnose growth hormone (GH) deficiency. Because it may be misused in expectation of a growth-promoting effect by athletes, the illicit use of GHS by athletes has been prohibited by the World Anti-Doping Agency (WADA). Therefore, the mass spectrometric identification of urinary GHRP-2 and its metabolite D-Ala-D-(β-naphthyl)-Ala-Ala-OH (AA-3) was studied using liquid chromatography/electrospray ionization tandem mass spectrometry for doping control purposes. The method consists of solid-phase extraction using stable-isotope-labeled GHRP-2 as an internal standard and subsequent ultra-performance liquid chromatography/tandem mass spectrometry, and the two target peptides were determined at urinary concentrations of 0.5–10 ng/mL. The recoveries ranged from 84 to 101%, and the assay precisions were calculated as 1.6–3.8% (intra-day) and 1.9–4.3% (inter-day). Intravenous administration of GHRP-2 in ten male volunteers was studied to demonstrate the applicability of the method. In all ten cases, unchanged GHRP-2 and its specific metabolite AA-3 were detected in urine. Copyright © 2010 John Wiley & Sons, Ltd.

Ayako Ikekita - One of the best experts on this subject based on the ideXlab platform.

  • determination of growth hormone secretagogue Pralmorelin ghrp 2 and its metabolite in human urine by liquid chromatography electrospray ionization tandem mass spectrometry
    Rapid Communications in Mass Spectrometry, 2010
    Co-Authors: Masato Okano, Mitsuhiko Sato, Ayako Ikekita, Shinji Kageyama
    Abstract:

    GHRP-2 (Pralmorelin, D-Ala-D-(β-naphthyl)-Ala-Ala-Trp-D-Phe-Lys-NH2), which belongs to a class of growth hormone secretagogue (GHS), is intravenously used to diagnose growth hormone (GH) deficiency. Because it may be misused in expectation of a growth-promoting effect by athletes, the illicit use of GHS by athletes has been prohibited by the World Anti-Doping Agency (WADA). Therefore, the mass spectrometric identification of urinary GHRP-2 and its metabolite D-Ala-D-(β-naphthyl)-Ala-Ala-OH (AA-3) was studied using liquid chromatography/electrospray ionization tandem mass spectrometry for doping control purposes. The method consists of solid-phase extraction using stable-isotope-labeled GHRP-2 as an internal standard and subsequent ultra-performance liquid chromatography/tandem mass spectrometry, and the two target peptides were determined at urinary concentrations of 0.5–10 ng/mL. The recoveries ranged from 84 to 101%, and the assay precisions were calculated as 1.6–3.8% (intra-day) and 1.9–4.3% (inter-day). Intravenous administration of GHRP-2 in ten male volunteers was studied to demonstrate the applicability of the method. In all ten cases, unchanged GHRP-2 and its specific metabolite AA-3 were detected in urine. Copyright © 2010 John Wiley & Sons, Ltd.

  • Determination of growth hormone secretagogue Pralmorelin (GHRP-2) and its metabolite in human urine by liquid chromatography/electrospray ionization tandem mass spectrometry.
    Rapid Communications in Mass Spectrometry, 2010
    Co-Authors: Masato Okano, Mitsuhiko Sato, Ayako Ikekita, Shinji Kageyama
    Abstract:

    GHRP-2 (Pralmorelin, D-Ala-D-(β-naphthyl)-Ala-Ala-Trp-D-Phe-Lys-NH2), which belongs to a class of growth hormone secretagogue (GHS), is intravenously used to diagnose growth hormone (GH) deficiency. Because it may be misused in expectation of a growth-promoting effect by athletes, the illicit use of GHS by athletes has been prohibited by the World Anti-Doping Agency (WADA). Therefore, the mass spectrometric identification of urinary GHRP-2 and its metabolite D-Ala-D-(β-naphthyl)-Ala-Ala-OH (AA-3) was studied using liquid chromatography/electrospray ionization tandem mass spectrometry for doping control purposes. The method consists of solid-phase extraction using stable-isotope-labeled GHRP-2 as an internal standard and subsequent ultra-performance liquid chromatography/tandem mass spectrometry, and the two target peptides were determined at urinary concentrations of 0.5–10 ng/mL. The recoveries ranged from 84 to 101%, and the assay precisions were calculated as 1.6–3.8% (intra-day) and 1.9–4.3% (inter-day). Intravenous administration of GHRP-2 in ten male volunteers was studied to demonstrate the applicability of the method. In all ten cases, unchanged GHRP-2 and its specific metabolite AA-3 were detected in urine. Copyright © 2010 John Wiley & Sons, Ltd.